Method And Device For Representing A Digital Image On A Surface Which Is Non-Trivial In Terms Of Its Geometry And Photometry

Abstract

The invention relates to a method and a device for representing a two-dimensional digital image on a projection surface, whereby at least one projector projects the content of an image buffer onto the projection surface. The aim of the invention is to provide a method and a device which allow to project a digital image onto a background having any surface structure and / or color in such a manner that any influences on the image caused by the background are compensated to the last pixel for at least one special observer perspective. In a special embodiment, definition of the representation is optimized to the last pixel even on an uneven background. For this purpose, the digital image is processed during a rendering step by geometrically distorting it using a two-dimensional pixel-offset field which contains information on the projection surface, and by manipulating the color of the image by means of a two-dimensional surface texture of the projection surface. A least a part of the processed image is rendered in an image buffer and a rectangle is written into the image buffer for initiating the rendering step, thereby compensating scattered light influences. The invention especially relates to a system comprising a plurality of projectors. Definition of representation can be optimized to the last pixel by means of definition values and representation is furthermore possible subject to the observer's position.

Description

BACKGROUND OF THE INVENTION [0001] The invention relates to a method and an apparatus for representing a digital image on a projection surface, and the content of an image buffer being projected onto the projection surface by means of a projector. [0002] In the context of the invention, a projection surface is in principle any desired surface. In particular a projection surface in the context of the invention can be a surface that is non-trivial in terms of geometry and photometry that, for instance, has any desired three-dimensional shape and / or any desired texture. In the context of the invention a projection surface can in particular also comprise a plurality of partial surfaces. [0003] A system is known from DE 102 51 217 B3 for automatic calibration of multiple projector systems that has at least two projectors, one digital camera, and a control unit for controlling the projectors and the camera, automatic calibration occurring with the steps of generation, recording and image ...

AI Technical Summary

Benefits of technology

[0017] The object is attained using a method that with the method according to the invention it is possible to correctly project a digital image that can also come from a series of images to be projected sequentially, with one or a plurality of projectors, onto a non-planar surface that is very complex in terms of geometry and that is colored and / or textured in that form and color information for the surface are included in an adaptation of the digital images. The method provides that the digital image is processed during a rendering process in which it is geometrically distorted using a two-dimensional pixel displacement map that contains pixel-exact information about the projection surface and / or the color is manipulated using a two-dimensional surface texture of the projection surface, and in which at least a part of the processed image is rendered into the image buffer. The method is able to process and represent each pixel of the projector or projectors in real-time.

[0018] It is in particular advantageous that there is a pixel-exact geometric or color correction of the digital image, that the measurement of the surface geometry and the surface texture of the projection surface and environmental illumination in a calibration can occur fully automatically and pixel-exact, and that the method can be performed with modern computer hardware in the form of pixel shaders at high speed, in particular in real-time.

Problems solved by technology

Pixel-exact warping is not possible with this system.

It is furthermore disadvantageous that non-white texturizing or differences in texturizing of the projection surface have a negative effect on the display.

Recordings of natural scenes, especially in the dark, frequently do not have high contrast and therefore do not have an adequate number of edges.

This has a negative effect on the quality of the passive autofocus mechanisms in the cameras.

Defocused projection causes them to become even less defined, which distorts the depth perception.

However, this solution is extremely costly.

In addition, the laser projectors used have a major disadvantage.

Mobile use of laser projectors is therefore very complex.

These methods are not suitable for representing moving contents with active display devices such as projectors.

Images